Problem: Ashley ate 2 slices of pie. William ate 5 slices. If Ashley ate $\dfrac{2}{12}$ of the pie, what fraction of the pie is remaining?
If 2 slices represent $\dfrac{2}{12}$ of the pie, there must have been a total of 12 slices. $\text{fraction of pie remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 7 slices, which leaves 5 out of 12 slices remaining. There is $\dfrac{5}{12}$ of the pie remaining.